1. Field of the Invention
The present invention is related to a calibration method and capacitive sensing device, and more particularly, to a calibration method and capacitive sensing device which suppress noises in a mutual-sensing mode with help from a self-sensing mode.
2. Description of the Prior Art
With advances in touch control technology, conventional keyboards and mice are gradually replaced with touch panels in electronic devices. The touch panel is plied upon a display panel, and a user can tab the display panel via a finger or a touch pen to operate the electronic device. As a result, since the conventional keyboard area is no longer required in the front surface of the electronic device, the display area can be enlarged on the electronic device.
A user instruction sent to the touch panel can be sensed based on resistance, capacitance, light or sound change around the touch panel. Particularly, the capacitive touch panel has great sensitivity to the user instruction, and is widely employed various kinds of electronic devices. The capacitive touch panel determines a touched region according to a capacitive change of the touch panel. However, other than the capacitors designed by the manufacturer, there is a parasitic capacitor in the touch panel. The parasitic capacitor results in a bias in a touch sensing signal, which misguides the consequent touch recognition process. Therefore, the bias of the touch sensing signal has to be canceled.